Avery Bradley talks glowingly of Avery Bradley III, mentioning that his son is totally attached to his father, crying for long stretches when Dad hits the gym for one of his three daily workouts.

Bradley’s mind is free entering his fifth NBA season. He just agreed to a four-year, $32 million contract. He enters Celtics’ training camp next month completely healthy and a year removed from his mother’s unexpected death.

The basketball court has been the 23-year-old guard’s place of solace. He said there are times this summer when he has worked out in Waltham and driven home after a rigorous session, only to drive back to Waltham to work on a drill he felt he ignored.

The Celtics have eagerly waited for Bradley to physically mature as well as mentally develop. He appears ready for a breakthrough season after averaging 14.9 points last season, although he missed 22 games with an ankle injury.

Bradley has been working feverishly to strengthen his body, hoping to avoid injuries and develop into the Celtics’ shooting guard of the future.

“Basketball has been my getaway,” he said last week during his camp in Dartmouth. “Whenever I might have a bad thought in my head, I’ll just go to the gym. That’s how I relieve all my stress. Sometimes I’ll go to the gym five times a day. That’s really been my outlet. My friends call me a gym rat but even if I am just sitting in the gym, I’ll look at the court and just imagine myself on it sometimes.”

Bradley’s mother, Alicia Jones, died on Sept. 10, 2013, in Tacoma, Wash., and following her death Avery decided to split most of his time between Boston and Austin, Texas. He has avoided returning to Tacoma.

“I don’t really like to go back,” he said. “My siblings [are there] and I have a niece and a nephew there but that’s really the only reason I go back home. There’s too many memories. I don’t really go back home. I went back home this summer for two days.”

Having spent an injury-free summer working out and feeling rewarded by the Celtics’ surprising long-term investment, Bradley said he is determined to live up to expectations.

“I’m motivated to be the best teammate I can be,” he said. “One thing I want to improve this year is I want to get my teammates involved a little bit more [by passing the ball]. I know that’s something I can get better at, especially because the game’s slowing down for me. I’m willing to do whatever it takes.”

Bradley came into the NBA following his freshman season at the University of Texas a bright-eyed 19-year-old, but he is now the second-most tenured Celtic behind Rajon Rondo. And he laughs when told that rookie Marcus Smart is 3½ years his junior and James Young is nearly five.

“I remember KG [
Kevin Garnett] and those guys would tell me, 10 years is going to go by like that and I’m already five years in,” he said. “It hits home for sure because I’m taking a leadership role. I’m open to taking it and not only that, I’m excited to take it. I feel like I can teach the younger guys a lot, all the stuff that I’ve been through, all the stuff that I’ve learned from the amazing players I was blessed enough to play with.”

Bradley and Rondo are the Celtics’ projected starting backcourt and the two have grown closer over the years.

“He has helped me a lot,” Bradley said. “It just shows, man, I just love playing with him. I know he’s happy here. I know he likes the whole organization and this is his home now and I know that he’s comfortable here and we’re all happy to have him here.”

The decision to re-sign was not difficult for Bradley. He and the Celtics were unable to agree on a contract extension last October, making him a restricted free agent, which allowed other teams to make offers.

The Celtics did not let the process to advance that far.

“I just remember I had a decision to stay in my second home, really,” he said. “I’ve been living here for four years and I love playing under [president of basketball operations] Danny Ainge and [coach] BradStevens. It was a no-brainer. They were the first team that called. We had other calls but Boston, I knew I was coming back here.”

And the thought of sharing the backcourt with Rondo — now that both players are completely healthy, with Rondo spending much of last season recovering from a torn right ACL — is exciting to Bradley.

“A lot of people might say we can’t be this or we can’t be that but I feel like with the coach we have, we can be anything we want to be,” Bradley said. “We all just have to listen to him and buy into what he’s trying to do, his plan for us. I feel like we have a chance to make the playoffs and to make a lot of noise this year, if we listen to Brad.

“I feel like we have a chance to be a top-10 defensive team in the NBA this year. We’re all fired up. Jeff Green as well. We’re all excited about this season. We have a lot of good additions.”

UP TO THE CHALLENGE

Roberts well suited for role as union boss

Now that the Players Association has hired Michele Roberts as its executive director, making her the first woman to lead a North American men’s sports union, the challenge is to build relationships and negotiate with the heavy-handed NBA, led by former lawyer Adam Silver.

Under previous executive director Billy Hunter, the NBPA shared a strange relationship with the league. There were times Hunter and former commissioner David Stern were involved in heated exchanges during labor talks, accusing each other of deceitful practices, and there were also times the two 71-year-olds were laughing and shaking hands during league events. They shared a healthy respect for each other but represented opposite sides and opposite viewpoints.

Roberts said she is preparing for an interesting relationship with Silver, and won’t allow her gender to factor into her dealings with the NBA.

“The work that I have been doing at my firms for the last 15 years, I represent corporate America, I represent very powerful people,” said Roberts, a lawyer in the firm of Skadden, Arps, Slate, Meagher and Flom. “Financial institutions, insurance companies, pharmaceutical companies — very, very powerful people. Many, I must confess, most of them were white and most of them were male. I’ve had to negotiate with them, I’ve had to fight with them, I’ve had to bargain with them. They trust me. I’m not intimidated by that kind of character, I have known them for years.

“I also discovered at a certain level — and I include the owners and players in this— people are more interested in what you bring to the table, what you’ve got by the way of leverage than the fact that you’re wearing a skirt. I don’t spend much time reminding myself that most of the people I’ll be dealing with are men. It’s never worked for me to be conscious of it.”

Roberts, however, could not ignore the significance of her hiring, especially when her two basketball-crazed brothers expressed unrelenting pride in their sister.

“I’ve got two young nieces who I worship and adore and they view this as more confirmation of what I’ve been telling them all their lives, that there’s nothing you can’t do if you work hard at it,” Roberts said. “I’ve enjoyed the moment. It’s been great. You could imagine that I’ve gotten people writing to me and calling me that I haven’t heard from in years. For me, personally, it’s going to be a fabulous pivot to what has been a fabulous career. I haven’t been unhappy in my work.”

SIGN OF THE TIMES

Lack of true centers not lost on Mourning

Alonzo Mourning was inducted into the Naismith Memorial Hall of Fame two weeks ago, having earned his way there as a true center. But legitimate big men in the middle are dying out. Team USA, for example, has had a difficult time finding centers to fill out the roster, relying on youngster Andre Drummond and the mercurial DeMarcus Cousins because of the dearth of big men.

Mourning said that if he played today, he’d probably be transformed into a stretch-4 or perimeter shooting power forward. The lack of centers is not surprising to Mourning, now an executive with the Miami Heat.

“I wouldn’t say it’s leaving because if another great center comes along, he’ll be the first pick in the draft,” he said. “[Joel] Embiid would have been the first pick in the draft if not for his health.

“Basketball is played from the inside out. San Antonio beat us [Miami in the NBA Finals] because they dominated us in the paint. So if you can get somebody in the draft that’s dominating in the paint, they’re going to go first.”

“They’re not teaching fundamentals of the game,” he said. “They’re not teaching the game inside out. Why do you think Tim Duncan is still dominating the game. He’s literally still having an impact on the game at his age because he’s so fundamentally sound. The game is changing because the game isn’t being taught the way it was being taught back in the day. You don’t have as many qualified coaches as you did. You don’t have your John Thompsons, your NolanRichardsons, your Dean Smiths, your Bobby Knights.

“The last of them all is Coach K [Mike Krzyzewski]. But those coaches know the game is played from the inside out. The best shot in the game is a layup.”

While the development of the stretch-4 has made the NBA more exciting and versatile at the offensive end, it has also turned some of the game’s top 7-footers into jump shooters with underdeveloped post games.

“You look at more and more of these kids — Kevin Durant, 7 feet, Dirk Nowitzki, 7 feet, LeBron [James], 6-9. I mean, the list goes on,” Mourning said. “These tall guys, they’re gravitating towards the perimeter. And the reason why is that’s not how they were taught [to play inside].”

Mourning said his coaching tree enabled him to learn to play center. He played at Georgetown for Thompson, who was Bill Russell’s backup in Boston for the 1964-65 season.

“First, I had a [high school] coach [Bill Lassiter] who was taught by John B. McClendon, who was taught by James Naismith, then I had a college coach who was a center that played behind Bill Russell. I was taught the game from the post. I could have easily been one of those jump-shooting big men.”

An interesting twist in the development of the stretch-4 is that Mourning’s son, Trey, is a 6-9, smooth-shooting power forward headed for Georgetown.

“That’s what my son is, my son is a stretch-4,” Mourning said. “He’s 6-9 and shooting the heck out of the ball from the outside. The only thing holding my son back right now is his strength and his speed. The only thing that he has better than what I had is he can flat-out shoot the ball. It’s just how the game is being taught now.”

ETC.

Celtics’ roster for camp at 21 after invitations

The Celtics have invited former Penn State guard Tim Frazier, Kansas State swingman Rodney McGruder, and Indiana forward Christian Watford to training camp, according to reports. With Colton Iverson signing with a team in Spain and Mike Moser likely headed to another training camp, the Celtics will enter camp with 21 players.

Chris Babb and Chris Johnson are under nonguaranteed contracts and the club has yet to announce the Evan Turner deal, making their 15-man roster rather uncertain. Center Vitor Faverani remains under contract as well as Joel Anthony, who accepted his $3.8 million option for next season. Training camp is likely to remain at the team’s Waltham practice facility and not at Salve Regina in Newport R.I.

Celtics’ players are beginning to gather in Waltham to conduct workouts, including Avery Bradley, Brandon Bass, and Rajon Rondo.

Layups

While the Celtics are trying to figure out ways to clear roster space before training camp, moving Rondo is not a high priority. First off, Rondo will be a free agent next summer and fully intends on taking the LeBron James-Carmelo Anthony tour of teams and extending the negotiation process deep into next summer. It is highly unlikely Rondo would sign an extension this season with an interested team, especially the Sacramento Kings. Second, the Celtics don’t feel pressed to deal Rondo because they are still trying to determine if he’s part of the future and they are intrigued to see him in action a full 18 months following ACL surgery . . . James and manager Maverick Carter have developed a six-episode series for the Starz network called “Survivor’s Remorse” about a basketball player who signs a mega-contract with a team in Atlanta and has to deal with the challenges of his newfound stardom. The series is based loosely on James’s life. Carter and Tom Werner are executive producers while Mike Epps and
Tichina Arnold star in the series, which will premiere Oct. 4 . . . It looks as if Phoenix guard Eric Bledsoe will sign the qualifying offer to return to the Suns, but there has been some hard feelings during contract negotiations. Bledsoe may be inclined to bolt as an unrestricted free agent next summer. The Celtics have always liked Bledsoe and he could be a potential replacement for Rondo, if he were to leave . . . The Memphis Grizzlies signed mammoth power forward Jarnell Stokes, their second-round pick, to a three-year contract. Stokes, at 6-8 and a chiseled 270 pounds, proved physically able to make the adjustment to the NBA during the Orlando Summer League. Had he remained at Tennessee for another season, he could have been a potential lottery pick. The Grizzlies also scored big in the draft by taking UCLA’s Jordan Adams, who dropped some weight and could be a Rookie of the Year candidate . . . The Cavaliers staff definitely has a Celtics flavor as former swingman James Posey was named to David Blatt’s staff and ex-center Vitaly Potapenko retained his job as assistant director of player development. Posey had coached the past few seasons with Canton of the Development League . . . 76ers coach Brett Brown was inducted into the Maine Basketball Hall of Fame’s first class. Brown was a two-time All-State player at South Portland High School. He went on to play at Boston University under Rick Pitino.

Gary Washburn can be reached at gwashburn@globe.com. Follow him on Twitter @GwashburnGlobe. Material from interviews, wire services, other beat writers, and league and team sources was used in this report.